Generally in video systems live video is captured and stored in memory, and fed into a video processing unit before being sent out for display on a video output device. Processing can involve such functions as, for example, scaling, compositing, and format conversion. Scaling can be horizontal and/or vertical, where scaling in one direction can involve increasing or decreasing the pixels per line, thus increasing or decreasing the size of an image and its format. Compositing can involve overlaying the video with a layer of graphics or text. Such processes may have an effect on the bandwidth of the memory of the system. For example, format conversions often cause an increase or decrease in the amount of memory required for capturing an input or an output into the memory.
In some instances, the size of the video captured is larger before processing than afterwards. In such instances, the system uses more bandwidth for capturing the video than may be necessary. In other instances, capturing the video before processing is more efficient, since some scaling and format change can convert the video to a size or format that requires more bandwidth.
Most systems require different memory bandwidth usage for each format and for different scale factors. In some instances cropped images and PIP images can have very large memory bandwidth, which can approach infinity because an entire source image needs to be read within a small fixed amount of time. This can cause serious malfunctions and problems in video systems. Some designs have attempted to solve this problem by detecting format changes and whenever a format change was detected, the rate at which data is captured in the system gets changed. The problem is that changing the rate at which data is captured every time there is a format change at the input and/or the output can become inefficient.
Further limitations and disadvantages of conventional and traditional approaches will become apparent to one of skill in the art, through comparison of such systems with some aspects of the present invention as set forth in the remainder of the present application with reference to the drawings.